1. Field of the Invention
The present invention relates to an input device, and in particular, to an input device with a multi-directional roller assembly for executing a command or scrolling an image on a display of a computer.
2. Description of the Prior Art
An input device, such as a computer mouse, usually has a left button to execute a command when locating the cursor at a specific position, and a right button to activate an extra function block on the screen. In addition, many peripheral devices, including computer mouses, keyboards, trackballs, game controllers, and so forth, have an additional scrolling roller for scrolling images on a display without the need to position a cursor. However, the progressive price reductions of such devices in recent years has made it extremely difficult to make a profit on such devices, and therefore control of costs has become critical. The invention proposes to control costs by eliminating the buttons, and instead providing a roller assembly that carries out the functions of the button and in addition serves as a scroll wheel, and yet has a very simple structure.
The most known related skill for scrolling images in WINDOWS™ applications is disclosed in U.S. Pat. No. 5,530,455, which shows a roller on the top of a mouse for vertically scrolling a content of a WINDOWS™ application. This roller is used solely for scrolling and cannot replace the conventional buttons used for executing commands or activating extra function blocks. Furthermore, use of the scroll wheel is limited to vertical scrolling if a user wishes to scroll the content differently, the user has to additionally press a Shift key on a keyboard and then rotate the roller to scroll the content horizontally. Alternatively, if the user is willing to spend more energy of movement to move the cursor to the horizontal scrolling bar and rotate the roller or draw the scrolling bar, then the user can scroll the image horizontally without using the shift key on the keyboard.
In order eliminate the need to press the shift key to achieve horizontal and vertical scrolling, U.S. Published Patent Application No. 2003/0025673 discloses a roller assembly which can be rotated for scrolling the image vertically (in an x-axis direction), or tilted to scroll the image horizontally (in a y-axis direction). This type of roller has the disadvantage that an optical encoder must be positioned within the roller assembly so as to detect the rotation of the roller in order to scroll the image in the y-axis direction. Due to the complex structure disclosed in the patent publication, the roller assembly has a very high cost, not only due to the need for precisely produced components, but also because of the difficulty of assembling the components of the roller.